1. Field of the Invention
The present invention relates to a liquid processing apparatus and a liquid processing method, which are configured to process an object to be processed by using a temperature-regulated liquid. In addition, the present invention relates to a storage medium storing a program for performing the liquid processing method configured to process an object to be processed by using a temperature-regulated liquid.
2. Description of Related Art
There has been generally, conventionally employed a technique for processing an object to be processed while supplying the object to be processed with a temperature-regulated liquid, such as an etching process for etching a semiconductor wafer (hereinafter referred to simply as “wafer”) or a glass substrate for display (e.g., JP2007-123393A). In general, when the temperature of a liquid for use in a process is high, reaction caused by the liquid is activated, which accelerate the process. Thus, heating of the liquid used in the processing offers such an advantage as reduction of the process period.
In addition, the inventors of the present invention have found that, when a drying liquid typified by IPA (isopropyl alcohol) is heated, such a heated liquid can be advantageously used in a drying process of an object to be processed such as a wafer. To be specific, when a heated drying liquid is used in a drying process of an object to be processed, an endothermic amount from the object to be processed is decreased upon evaporation of the drying liquid, whereby lowering of the temperature of the object to be processed can be restrained during the drying process. Thus, dew condensation on the object to be processed can be restrained, and generation of watermarks on the object to be processed can be effectively prevented.
When the temperature of the liquid used for processing the object to be processed is regulated, the progress of the process largely varies depending on the temperature of the liquid, as described above. Thus, it is important to maintain constant the temperature of the liquid used in the process, in order to ensure the uniform process.
JP2007-123393A discloses a substrate processing apparatus including: a tank storing a chemical liquid; a main pipeline (supply pipeline 163 for chemical liquid process) whose one end is connected to the tank; a plurality of supply pipelines (supply pipelines 64, 83 for chemical liquid process) branched from the other end of the main pipeline; and a plurality of processing units connected to the supply pipelines. In this substrate processing apparatus, a temperature regulating mechanism for regulating the temperature of a chemical liquid is disposed on the main pipeline, and the respective supply pipelines are provided with valves. By opening and closing the valves, a temperature-regulated chemical liquid is supplied to the respective processing units.
In this conventional substrate processing apparatus, when the valve is closed, the temperature-regulated chemical liquid will not flow through the supply pipeline. For example, in a case where the liquid is heated by regulating the temperature, when the process in the processing unit is stopped, i.e., when the supply of the heated liquid into the processing unit is stopped, the temperature of the supply pipeline lowers. Thus, upon restart of the supply of the heated liquid into the processing unit, the heat of the heated liquid is absorbed by the supply pipeline whose temperature has lowered, so that the temperature of the supplied liquid to be used for the process lowers.
In particular, as compared with the pipeline, the valve provided on the supply pipeline has a significantly larger heat capacity. Thus, while the supply of the temperature-regulated liquid into the processing unit is being stopped, if the temperature of the valve as well as the temperature of the supply pipeline vary (e.g., lower), the temperature of the liquid largely varies upon restart of the supply of the liquid into the processing unit. As a result, the process to the object to be processed may become unstable.